Update installation instructions

This patch adds information about installing from crates.io and suggests
checking out the latest release when installing from source.

INSTALL.md

@@ -5,24 +5,36 @@ SPDX-License-Identifier: MIT
 
 # Installing rusty-man
 
-## Installing from source
+## Requirements
+
+To compile rusty-man, you need Rust 1.40 or later.
 
-To install rusty-man from source, you need Rust 1.40 or later.
+## Installing from source
 
 1. Clone the rusty-man Git repository:
    ```
    $ git clone https://git.sr.ht/~ireas/rusty-man && cd rusty-man
    ```
-2. Optional:  Verify the signature of the latest commit:
+2. Optional:  Checkout the latest release:
+   ```
+   $ git checkout v0.1.0
+   ```
+3. Optional:  Verify the signature of the latest commit:
    ```
    $ curl -s "https://pgp.ireas.org/0x6D533958F070C57C.txt" | gpg --import
    $ gpg verify-commit HEAD
    ```
-3. Compile rusty-man:
+4. Compile rusty-man:
    ```
    $ cargo build --release
    ```
-4. Optional:  Install the rusty-man binary:
+5. Optional:  Install the rusty-man binary:
    ```
    $ sudo cp ./target/release/rusty-man /usr/local/bin/rusty-man
    ```
+
+## Installing from crates.io
+
+```
+cargo install rusty-man
+```

README.md

@@ -54,8 +54,9 @@ For more usage information, run `rusty-man --help`.
 
 ## Installation
 
-To install rusty-man, clone this repository and use cargo to build the project.
-See the [`INSTALL.md`](./INSTALL.md) file for more information.
+To install rusty-man, clone this repository and use cargo to build the project,
+or use `cargo install`.  See the [`INSTALL.md`](./INSTALL.md) file for more
+information.
 
 rusty-man should run on all platforms supported by [`crossterm`][].  If you
 have trouble running rusty-man on your platform or if you want to help porting